From: Jeff Garzik <jeff@garzik.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Robert Hancock <hancockr@shaw.ca>,
Zoltan Boszormenyi <zboszor@dunaweb.hu>,
Peer Chen <pchen@nvidia.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drivers/ata: Add the SW NCQ support to sata_nv for MCP51/MCP55/MCP61
Date: Fri, 18 May 2007 10:34:35 -0400 [thread overview]
Message-ID: <464DB97B.8030204@garzik.org> (raw)
In-Reply-To: <20070518133456.5f1392e9@the-village.bc.nu>
Alan Cox wrote:
>> That shouldn't be a problem, libata default DMA mask is 32 bits (which
>> isn't overridden with this controller) and so the block layer will
>> bounce any data being read/written above that point with IOMMU or
>> swiotlb. The comment is a bit unnecessarily scary.
>
> Adding a BUG_ON for this would be wise. Its trivial to check and a BUG
> rather than corruption if this assumption ever changes would be far
> preferable
The default DMA mask -everywhere- is 32 bits.
A lot of code will break if this assumption ever changes, not just libata.
Jeff
next prev parent reply other threads:[~2007-05-18 14:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <fa.iernIz8Xcuvw0SBwi4A99Ju0g2o@ifi.uio.no>
2007-05-18 1:58 ` Robert Hancock
2007-05-18 12:34 ` Alan Cox
2007-05-18 14:34 ` Jeff Garzik [this message]
2007-05-18 15:12 ` Alan Cox
2007-05-20 8:34 ` Zoltan Boszormenyi
[not found] <fa.NGBsZzMiMJ9x7V/pv+sqAv36hwA@ifi.uio.no>
2007-05-18 23:31 ` Robert Hancock
2007-05-18 11:10 Kuan Luo
-- strict thread matches above, loose matches on Subject: below --
2007-05-17 21:02 Zoltan Boszormenyi
2007-05-15 6:22 [PATCH] drivers/ata: correct a wrong free function for sata_nv driver Peer Chen
2007-05-16 5:21 ` Jeff Garzik
2007-05-17 10:15 ` [PATCH] drivers/ata: Add the SW NCQ support to sata_nv for MCP51/MCP55/MCP61 Peer Chen
2007-05-17 20:12 ` Andrew Morton
2007-05-17 20:17 ` Andrew Morton
2007-05-17 21:11 ` Jan Engelhardt
2007-05-18 1:47 ` Robert Hancock
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